SOLUTION: To cover 14 km distance , anubhav cycles at a certain average speed. If he reduces his average speed by1 km/hr , he takes 20 min more to cover the same distance. find the original

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: To cover 14 km distance , anubhav cycles at a certain average speed. If he reduces his average speed by1 km/hr , he takes 20 min more to cover the same distance. find the original       Log On


   

Question 696811: To cover 14 km distance , anubhav cycles at a certain average speed. If he reduces his average speed by1 km/hr , he takes 20 min more to cover the same distance. find the original speed.
Answer by stanbon(75887) About Me  (Show Source):
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To cover 14 km distance , anubhav cycles at a certain average speed. If he reduces his average speed by1 km/hr , he takes 20 min more to cover the same distance. find the original speed.
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1st trip DATA:
distance = 14 km ; speed = x km/hr ; time = 14/x hrs
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2nd trip DATA:
distance = 14 km ; speed (x-1) km/hr ; time = 14/(x-1) hrs
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Equation:
time - time = 1/3 hr
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14/(x-1) - 14/x = 1/3
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3*14x - 3*14(x-1) = x(x-1)
42x - 42x - 42 = x^2 - x
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x^2 -x + 42 = 0
Factor:
(x-7)(x+6) = 0
Positive solution:
x = 7 km/hr (original speed)
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Cheers,
Stan H.
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